Series glow-plug



H. F.-PAYNE Er AL SERIES GLOW PLUG Filed May 25, 1933 d 7 L Wu. Ev. 8

March 13, 1934.

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INVENTORS Patented Mar. 13, 1934 SERIES GLOW-PLUG Hugh F. Payne, Long Island City, and George M.

-Paulson, New York,

N. Y., assignors to The B. G. Corporation, New York, N. Y., a corporation of New York Application May 25, 1933, Serial No. 672,774

16 Claims.

This invention relates to electrical ignition plugs for internal combustion engines, and more especially to glow-plugssuch as are used in Diesel engines, for starting. Series glow-plugs, that is 3 to say plugs adapted to be connected electrically in series, are desirable because of economy of current, but their construction has presented difficulties. In a series glow-plug there must be two internal conductor pieces extending through ll the body, shell or barrel of the plug, to conduct current to and from the heating unit at the inner end of the plug, and these through conductor pieces must be insulated from each other and from the body. A concentric construction, in 1-; which one conductor piece is inside the other, is possible, but such a construction is troublesome to make, particularly for small diameter plugs, and is dimcult to make gas-tight.

An object of this invention is to provide a novel series glow-plug construction which has advantages in respect to compactness and cheapness of manufacture, in which neither of the through conductor parts need be very small, and with which it is easy to secure gas-tightness and easy to connect the heating unit to theseparts. A further object of the invention is to provide the plug with, and to adapt the plug to receive, a simple, compact, readily manufactured connec- ,tion terminal, which does not require and does not permit of the application of a tool in putting it on or taking it off the plug, which is easily applied I and removed with the fingers, and the applica-' tion and.removal of which can not cause any straining of the plug.

In the plug of this invention, two conductor pieces are disposed side by side, with insulation between them and insulation separating them from the body. In cross-sectional form, the conductor pieces are preferably segments of circles, so that the two pieces, together with the intervening insulation, form a split spindle or core of circular cross-section conforming to the opening through the body. By means of a taper or wedging means coacting between the spindle and the body, the conductor pieces and the insula- ,tions are firmly clasped in the body and pressed together so that gas can not escape through the insulation or between the conductor pieces orbetween them and the body. For the purpose of making these gas-tight seals, the insulations should be of a sufficiently flexible or compressible material rather than brittle or rigid. Layers of sheet mica between the conductor pieces and wrappings of mica about them are highly de- .sirable for this reason and also because with such insulation it is easy to make plugs of small diameter.

The conductor pieces are locked against longitudinal displacement in the body by a metal part encircling an upper portion of the split spindle, this part having been permanently deformed, preferably by a die-drawing operation, so as to grip the spindle and its parts in a powerful, unyielding embrace. A locking collar or sleeve separate from the plug body and bearing downward against it is preferably employed. If the locking portion is separate from the body, it prevents the spindle from moving downward in the body, while upward movement is prevented by the taper or wedge that seals theconductor pieces in the body. However, the permanently deformed lock-' ing portion may prevent displacement of the conductor pieces in both directions.

For the purpose of taking the terminal, the upper ends of the conductor pieces of the split spindle are cutaway at their confronting sides, so that a slot is provided between a pair of upstanding posts. The terminal is made with a central plate portion adapted to be slipped between these posts and with bent conductor wings set out from the plate to clasp the outer surfaces of the posts. These wings are electrically connected, respectively, with binding bolts that pass through the end portions of the plate and are adapted to receive the conductor wires. The plate portion of the terminal preferably consists of a flat bar of insulating material faced on both sides with conductor plates to contact with the inner surfaces of the posts.

In the accompanying drawing, forming part hereof:

Fig. l is a longitudinal section through a series glow-plug and terminal embodying the features of the invention;

Fig. 2 is an elevation on a smaller scale, looking at right angles to Fig. 1;-

Fig. 3 is a cross-section on the line 3-3 of Fig. 1; and

Fig. 4 is a cross-section'on the line 4-4 of Fig. 2, this view being on the same scale as Figs. 1 and 3.

The generally cylindrical, hollow body 2 of the preferred embodiment of the'series glow-plug of I the the invention has a shoulder 3 to receive the thrust of a not (not shown) by which the plug is held in the ignition plug opening of the engine cylinder. A beveled nose 4 at the inner end of the body is then pressed tightly against a corresponding seating surface in the engine casting. However, it will be understood that the plug may be secured in the engine in any suitable-manner.

The opening through the body 2 is of circular cross-section, and the split spindle 5 is likewise of circular cross-section. The term split spindle is used for convenience. Actually, there are two separate conductor pieces 6, 6, each of segmentshaped cross-section. These pieces are preferably of the same proportions, the cross-section of each gether with the interfacial insulation 8, when pressed together, present circular cross-sections. Mica insulation 9 is wrapped about the split spindle, this insulation being coextensive with the portion of the spindle that is surrounded by the body. The ends of the heating unit '1 are fixed in holes 'drilledintheinnerendsoftheparts6,6,.orare otherwise suitably secured thereto.

Reference has been made to the creation, by

- means of a wedge or taper, of sealing pressure between the body 2, the conductor pieces 6, 6, and the insulations 8 and 9, which insulate the conductor pieces .from each other and both pieces from the body. The particular construction which is illustrated gives very effective multiple sealing andis alsosimpletomakcandcompact. In this construction, a portion at least of the opening through the body2 is; made with a taper, increasing in diameter downwardly or toward the inner end of the body. The curved surfaces of the portions 10 of the conductor parts 6 are made witha similar taper, so that thecircular crosssection of the split spindle increases in the same direction. J

In assembling the plug, the two parts 6, 6, with the insulation 8 between them and the insulation 9 wrapped about them, are inserted into the body 2, and then, while either the spindle or the body is supported, the other is forced under consider able pressure in the direction that crowds all the internal parts tightly within the body. This squeezes the insulation 8 and 9 suiliciently to insure leak-tight seals between the faces of the parts6,6andbetweentheperiphery oftheasaociated parts and the inner wall'surface of the body.

I, secure, however, to keep the parts 6, 6 from becoming loose in service and slipping downward relativelytothebody. Ifthatoccurred,thegas sealing would, of course,be 1m. In order to produce an absolute-lock, a metal partsurrou'nd ing portions of the conductor parts 6, 6 above the taper is permanentlydistorted as the result of to employ a separate collar or sleeve 12 which is placed around the parts 6, 6 and the insulations immediately above the body 2 Permanent compression' of this sleeve is best produced by drawin: a die downward over the sleeve, such die hav- Because'of the low ing an opening the diameter of which is somewhat less than the original external diameter of the sleeve. The distortion of the sleeve is such that the sleeve is not only permanently contracted but is elongated downward, and by the latter action forced against the shoulder presented by the upper end of the body. In this connection, it is advantageous to dispose a few mica washers 13, or some other yielding or elastic packing, between the adjacent ends of the sleeve and body. This elastic packing is strongly compressed by the longitudinal flow of the metal of the sleeve 12,

with the result that not only does stress exist betweenthe locking sleeve and the body, but also the compressed packing 13 contributes to an upward reaction on the spindle parts, which aids to keep the taper fit and the gas seals inside the body tight at all times. It should be understood, however, that the packing 13 may be omitted and the sleeve 12 be worked so that it bears down directly on the body.

It will be appreciated that the tremendously powerful, circumferentially uniform grip which the sleeve 12 exerts on the insulation wrapping 9, the parts6, 6 and the diametrical insulation 8, together with the compression of the pack ing 13, is serviceable for sealing as well as for locking. If by any chance gas should be able to make its way through the sealswithin'the body, it would be prevented from passing upward through the zone of excessive compression ,inside the locking collar or 'outward through the packinglii. It'may, therefore, be considered to be within the scope of the invention if I jlirodge or taper sealing were not specially provided for.-. v a

The insulations 8 and 9 need not necessarily be continuous throughout their respective ex- 2 ents lengthwise of the plug. Indeed, it is virtually necessary to make the portion of the mica wrapping 9 that encompasses the tapered-part of the split spindle separate from the wrapping that surrounds the cylindrical part of the spindle above the taper. Also, suflicient clearance nt-y be provided between this cylindrical part of the spindle and the cylindrical upper portion of theopening through the body 2 to per- The upper of-the conductor parts 6, 6 extend above the lock 12, and the inner, opposing faces of these extensions 14 are cut back, so

that a vertical slot 15 is created. Thus, the ex- 'wedgingfltalonemaynotbemfllciently tensions'ld resemble a pair obsubstantialposts having cylindrically curved outer surfaces and spaced, flat innersurfaces. '5

To these posts the terminal 16 is applied. 'lhis terminal comprises a transverse plate por-y tion 1'! adapted to fit the slotbetween the posts, binding screws or bolts 18 passing through the end portions of the plate, at opposite sides of the posts, and reversely arranged resilient conductor wings 19 set out fromthe central portion of the plate, between the binding bolts, these 1 88 being curved to-clasp the curved outer outward to form the conductor wing's19, one end of each of which is free. These conductor wings are preferably slotted, as seen in Fig. 2, to increase their flexibility.

The binding bolts 18 are passed in reverse directions through openings in the parts 20, 21 and 22, all of which are clamped between the heads of the bolts and nuts 23. Flanges 24 bent from the conductor pieces 22 and bearing against the ends of the plate portion of the clip prevent any possibility of these pieces turning about the bolts. The conductor wires are held between the nuts 23 and other nuts 25. One of the bolts 18 is in electrical connection with the flat conductor piece 21 and the winged conductor piece 22 at one side of the plate, and is insulated from the piece 21 at the opposite side of the plate by an insulating washer 26. The conductor pieces 21 and 22 at the opposite side of the plate are in electrical connection with the other bolt 18, and this bolt is insulated from the piece 21 at the other side of the plate by means of another insulating washer 26. Thus, the conductor pieces 21 and 22, at one side of the plate, which embrace one of the posts 14, are connected with one side of the circuit, while the conductor pieces at the opposite side of the plate, which embrace the other of the posts, are connected with the other side ofthe circuit.

This terminal can be applied easily to the glowplug by a straight push, and can be as easily removed.

While the preferred embodiment of the invention has been described in detail, it will be evident that the construction is susceptible of modification without departing from essentials.

We claim:

1. A series ignition glow-plug, comprising body, a heating unit, and two conductor pieces extending through the body and to which the heating unit is connected, said conductor pieces being of segmental cross-section, with insulation between their adjacent flat faces and a wrapped insulation between them and the body.

2. A series ignition glow-plug having a body, a heating unit, and a bilaterally symmetrical spindle comprising two conductor pieces of segmental cross-section, to which the heating unit is connected, and which are insulated from each other and from the body.

3. A "series ignition glow-plug having a body, two through conductor pieces of segmental crosssection, a heating unit connected to said conductor pieces, mica insulation between the opposed faces of said conductor pieces, and a wrapping of mica insulation about the conductor pieces.

4. A series ignition glow-plug having a body, two through conductor pieces side by side, to which a heating unit is connected, compressible insulations between and around said conductor pieces, and means, comprising a taper formation, claspingsaid conductor pieces and compressing said insulations within the body, to form gastight seals between said pieces and between them and the body. 1

collar having been permanently distorted by temporarily applied force so as to hold said conductor pieces in an unyielding grip.

'7. A series ignition glow-plug having a body, two through conductor pieces to which a heating unit is connected, said conductor pieces being side by side with insulations between and around them, means coacting between said conductor pieces and the body to prevent upward movement of said conductor pieces relatively to the body, and a lock collar encircling upper portions of said conductor and the insulation about them, said collar having been permanently distorted to hold said conductor pieces in an unyielding grip preventing downward movement of said pieces relative to each other and to the body.

8. A series ignition glow-plug having a.body, two through conductor pieces to which a heating unit is connected, said conductor pieces being side by side with insulations between and around them, means comprising a taper formation between said conductor pieces and the body forming gas-tight seals and preventing upward movement of said conductor pieces relative to the body, and a permanently distorted lock collar encircling and gripping said conductor pieces and the insulation about them and coacting with the body to prevent downward movement of the pieces.

9. A series ignition glow-plug having a body provided with an opening having a taper, two conductor pieces of segmental cross-section, in-

sulation between the faces of said conductor pieces, insulation around the conductor pieces and separating them from the wall of the body, the curved surfaces of said conductor pieces having tapered portions to coact with the taper of the body opening, whereby the conductor pieces are wedged in the interior of the body and the insulations are compressed to form gas-tight seals, and a lock collar permanently distorted to grip said conductor'pieces and the insulations immediately above the body.

11. A series ignition glow-plug having a body,

two through conductor pieces to which a heating unit is connected, said conductor pieces being side by side withinsulations between and around them, means preventing upward movement of the conductor pieces relative to the body, and a lock collar encircling the conductor pieces immediately above the body, said'lock collar having been permanently distorted to grip said pieces and to exert downward pressure on the body, creating an upward reaction on the conductor pieces.

12. A series ignition glow-plug having a body,

'spectively, .with said binding bolts.

two through conductor pieces towhich a heating unit is connected, said conductor pieces being side by side with insulation between and around them, means preventing upward movement of the conductor pieces relative to the body, a lock collar encircling the conductor pieces immediately above the body, and a compressible packing interposed between said collar and the body, said lock collar having been permanently distorted to grip said conductor pieces and compress said packing.

13. A series ignition glow-plug having a body, two through conductor pieces to which a heating unit is connected, said conductor pieces being side by side with insulations between and around them, means preventing upward movement of the conductor pieces relative to the body, a lock collar encircling the conductor pieces and insulations immediately above the body, and a compressible packing interposed between said collar and the body, said lock collar having been permanently distorted to grip said conductor pieces and insulations and to compress said packing, whereby not only the conductor pieces are held unyieldingly against longitudinal movement but also gastight seals are formed by the compression of said 'insulations and of said packing.

14. The combination with a series ignition glowplug having a'body and two through conductor pieces disposed side by side and insulated from each other and from the body, the upper portions of said conductor pieces being formed to present a pair of spaced posts, of a terminal comprising a transverse part entered between said posts, binding bolts on saidtransverse part at opposite sides of the pair of posts, and conductor wings shaped and set out from the central portion of said transverse part to clasp the respective posts, said conductor wings being connected re- 15. The combination with a series ignition glow-plug having a body and twothrough conductor pieces disposed side by side and insulated from each other and from the body, the upper I spectively, in electrical contact with one of the conductor plates and insulated from the other, and two curved conductor wings to clasp the outer surfaces of the posts, said conductor wings being secured by and in electrical contact with the respective binding bolts.

16. The combination with a series ignition glow-plug having a body and two through conductor pieces of segmental cross-section disposed face to face and insulated from each other and from the body, the confronting fm of said con- .ductor pieces being cut back at the top to form two posts of segmental cross-section and intervening slot, of a terminal comprising a transverse part inserted in said slot and comprising two conductor plates insulated from each other to contact with the inner faces of said posts, a pair of curved conductor wings, likewise insulated from each other, to clasp the outer surfaces of said posts, and means, comprising binding bolts, for securing said conductor wingsand the elements of said transverse part together, and for connecting one of the conductor wings and one of the conductor plates with one conductor wire, and the other conductor wing and conductor plate with another conductor wire.

HUGH F. PAYNE. GEORGE pl. PAULBON.

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